I'm getting the following error on a fresh install of Zimbra 8.0.0_GA_5434:
451 4.0.0 Temporary message delivery failure try again (in reply to end of DATA command)
Mails are actually delivered to the various users, whilst also remaining in the deffered queue, they are therefore delivered over and over again. This doesn't happen to every message, but it happens fairly regularly.
I've run the command to set all zimbra permissions properly, but that hasn't helped.